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JohnMc last won the day on February 3 2016

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  1. Now if I could just convince the politicians of that....
  2. The essential element in any technical enterprise. Even the big boys follow that advise. GE is closing down their last CFL production facility and concentrating solely on LED lighting. Product demand for aquaponics should be long lived however. The demand for eating has not changed since our ancestors crawled off the savannah eons ago.
  3. No quibble on the differences Gary. I am looking at some of the old references in regards to the hydrostatic/dynamic aspects of the sand.
  4. Looking thru the old literature on hydro sand culture. Assumption being some research there might provide insight into the bed design for IAVs. Ran across this that might be of interest -- Pure sand can be used in trough or trench culture. However, in desert locations, it is often more convenient and less expensive to cover the greenhouse floor with polyethylene film and install a system of drainage pipes (PVC pipe 5 cm in diameter, cut one third through diagonally every 45 cm along the length of the pipe, with the cuts facing downward) and then to backfill the area with sand to a depth of approximately 30 cm. If the depth of the sand bed is shallower, moisture conditions may not be uniform and plant roots may grow into the drainpipes. The area to be used as planting beds may be level or slightly sloped. Supply manifolds for nutrient solution must be sited accordingly. Various kinds of desert and coastal sand with different physical and chemical properties have been used successfully by the University of Arizona workers. The size distribution of sand particles is not critical, except that exceptionally fine material such as mortar sand does not drain well and should be avoided. If calcareous sand is used, it is important to maintain a nutrient solution with a neutral pH, and increased amounts of chelated iron must be applied to the plants. Sand growing beds should be fumigated annually to prevent the introduction of soilborne diseases and nematodes. Irrigation practices are particularly critical during the high-radiation summer months, when crops may have to be irrigated as many as eight times per day. Proper irrigation is indicated by a small but continuous drainage, 4-7% of the application, from the entire growing area. Evaporation of water around small summer tomato transplants is often high, which can lead to a slight buildup of fertilizers in the planting bed. Extra nitrogen causes excessive vegetative growth, and reduces the number of fruits. This can be avoided by reducing the amount of nitrogen in the solution from the time of transplanting until the appearance of the first blossoms. Drainage from the beds should be tested frequently, and the beds leached when drainage salts exceed 3000 ppm. The principal crops grown in sand culture systems are tomato and cucumber, and yields of both crops can be high. Seedless cucumber production has exceeded 700 mt/ha. http://www.agnet.org/library.php?func=view&id=20110729175702
  5. Cecil, Aaaah now we get to the fins of the matter Another opportunity for regulatory over reach by the legislatures. Gak! In an ideal world I would love to see something like this. A new power complex that has the following: * Power plant. * Farming subsidiaries. * Aquaculture subsidiaries. * Bio recovery facilities. The thought. Power generates juice, their main product. The waste heat from the plant is sold to the subs. Imagine raising Tilapia in North Dakota in January. Either whole or partial discharge water from the aquaculture can be sold to the farming subs to water soil crops. Bio recovery facility creates fertilizer from the aquatic wastes sold to the soil farms. The waste from the fields are manipulated by the bio recovery as partial feed for the aquatic facility. Such an endeavor would sizeable and fights over land use would be a problem but it would make one heck of a goal.
  6. Personally I would put my bet on lack of, or insufficient market research. The second is lack of working capital. Generally the technical aspects of most businesses can be well defined. But a farming operation that can be impacted by environmental shifts, not having enough capital to weather several failures can be a killer.
  7. Well considering that in the US 4 out of 5 new businesses fail in the first 5 years, that is not bad. RAS is not exactly mainstream, requires unique conditions and well trained personnel.
  8. http://www.theengineer.co.uk/prize-winning-technology-to-make-the-desert-bloom/?cmpid=tenews_1866392 Interesting isn't it? In a conventional plot you want some clay to maintain water holding ability. In an aquaponic type type just the opposite.
  9. Seems to be the exception that proves the rule, worldwide.
  10. Yes indeed. Fact the observations presented could apply to nearly any type of business. A lot of business consultants are always pushing 'right sizing'. Sometimes its bunk, other times not. Rare for an inefficient firm to get big.
  11. Sand as an inorganic has one thing in its favor, it won't burn up in direct heat. If an IAVs operator had a cement kiln nearby they could sell the sand to them for use in cement co-products. Recycle the product.
  12. That might work. The problem is the water and sand ejecta outlet will have to be lower that the IAVs bed to work. Then you have to lift the sand by some means back into the bed.
  13. Here in the States, many water plants never toss their sand unless some persistent contaminate makes it unusable. They backflush/aerate the bed with the particulate captured in micro filter bags. Now follow me here cause I have never tested it. Flood the IAVs and keep it flooded. Insert a airlift sand pump into the bed. The ejecta is dumped into a portable tank the water returning to the bed. Once full, air is injected into the tank creating a fluid bed condition. Particulate captured in filter bags outboard the tank, cleansed water returned to the tank. Once cleaning is complete an outlet would direct the sand back into the bed. Heavy machinery for sure, but I suspect it will be offset by the labor savings. Any showstoppers to this idea?
  14. Thinking about it, if a facility was to go IAVs dedicated to toms a skinny sand bed that supports two rows is probably best. The vine could be trained along the floor next (as Gary suggests) to the growbed. I would not favor it but I using a net is an alternative --
  15. A case where it is a pleasure to be behind the curve so to speak.
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